Non-electric blasting caps initiatable by explosive energy from the detonation of an explosive gas mixture are disclosed and claimed in U.S. Pat. No. 3,885,499 to Hurley. These blasting caps contain an open space adjacent the ignition charge, a first conduit extending from outside the blasting cap into the open space in open communication with the ignition charge so as to convey the explosive gas as a confined stream into the open space for responsive ignition of the ignition charge; and a second conduit extending from the open space to the outside of the shell so that a stream of the explosive gas mixture can be continuously passed from the first conduit through the open space and through the second conduit to purge and charge the system for the detonation and responsive ignition of the ignition charge.
In the embodiments illustrated in the above patent, the cap shell is elongated and closed, including at one end a plug type closure member spaced from the ignition charge to form the requisite open space. Both conduits are plastic and thin walled for flexibility purposes. The first conduit extends into the shell through the end closure member and the second conduit extends from the open space either through the plug end closure or through the side of the cap shell.